Centruroides exilicauda have been considered separate species in the past, more recent taxonomic classification treats the two as one species It has two pinching claws anteriorly and a tail or pseudoabdomen that ends in a telson ( Fig 90.16 ), that houses a pair of poison glands and a stinger The animals are nocturnal; during the day they seek shelter under stones and debris They often crawl into sleeping bags, shoes, and unoccupied clothing The scorpion produces a neurotoxin and a local cytotoxin The neurotoxin (αtoxin) inhibits the inactivation of the voltage-gated sodium channels, which leads to prolonged depolarization and neuroexcitation affecting the autonomic and skeletal neuromuscular system Scorpion α-toxins also result in massive endogenous release of catecholamines and vasoactive peptide hormones, such as neuropeptide Y and endothelin-1 An estimated 10% of stings result in severe systemic envenomation Common symptoms include local pain, restlessness, hyperactivity, roving eye movements, and respiratory distress Other associated signs may include convulsions, drooling, wheezing, hyperthermia, cyanosis, abdominal pain, vomiting, GI hemorrhage, and respiratory failure Death may result from respiratory paralysis, pulmonary edema, or cardiogenic shock The diagnosis may be difficult because history of a sting may not be forthcoming especially since most bites involve children